Method of making electrotype printing plates



United States Patent [72] Inventor Robert E. Anderson Kalamazoo, Michigan [21] Appl. No. 747,599 [22] Filed July 25, 1968 [45] Patented Sept. 1, 1970 [73] Assignee Mueller Color Plate Company Battle Creek, Michigan a corporation of Wisconsin [54] METHOD OF MAKING ELECTROTYPE PRINTING PLATES 4 Claims, 7 Drawing Figs.

[52] U.S.Cl l0l/40l.1, 264/162 [51] Int.Cl B4ln 3/00 [50] Field ofSearch 101/401.1, 401.2,401.3;264/161, 162, 273

[56] References Cited UNITED STATES PATENTS 1,074,775 10/1913 Cornwall 264/273X Primary Examiner Robert E. Pulfrey Assistant Examiner-Clyde Coughenour AttorneyFred Wiviott ABSTRACT: The method of manufacturing an electrotype printing plate comprising the steps of electroforming a shell,

2 having raised characters on a front face and corresponding recesses on its back face, covering the back of the shell with nylon particles and placing a perforated draw member adjacent one edge of the plate. The nylon is fused to the back of the plate by heat and pressure, and a quantity is caused to flow over the one edge and to adhere to the screenlike member and fill a portion of the perforations therein. The draw member is attached to a carrier for pulling the plate through a shaving machine so that the nylon backing may be reduced to a uniform thickness and the draw member is then trimmed away.

Patented Sept. 1, 1970 3,526,190

FIGS

INVENTOR.

ROBERT E. ANDERSON BY 52% 00M Attorney BACKGROUND OF THE INVENTION This invention relates to a new and improved method for manufacturing a flexible electrotype printing plate.

Electrotype printing plates are generally manufactured by electrolytically depositing a metallic material, such as copper, on a mold to form a thin shell having raised characters on its front face and corresponding depressions on the back face thereof. When a relatively stiff plate is desired, the back is filled with a layer of material, such as lead, and then a composite plate is pushed through a shaving machine to shave the backing material and thereby reduce the plate to a uniform thickness.

When a relatively flexible plate is desired, a thermoplastic backing material, such as nylon, is employed. Because of their flexibility, such plates cannot be pushed through a shaving machine so that it is necessary to draw them through. In one prior art method involved in manufacturing such plates, the nylon material was caused to flow over the edge of the plate and to adhere to a carrier member, which was then pushed through the shaving machine with the plate adhering to its upper surface. After the shaving operation was completed, it was necessary to cut the plate away from the carrier, trim the excess material from the edges of the plate, and then to clean the carrier in preparation for another operation. The steps of cutting the plate from the carrier, trimming the plate and cleaning the carrier, lengthen the time required to manufacture the plates and correspondingly increase the cost of production.

It is an object of the invention to provide a new and improved method of manufacturing electrotype printing plates.

A more specific object of the invention is to provide a method of manufacturing electrotype printing plates, wherein the plate is not adhered to a carrier member.

These and other objects and advantages of the instant invention will become more apparent from the detailed description thereof taken with the accompanying drawings.

SUMMARY OF THE INVENTION In general terms, the invention comprises the method of manufacturing an electrotype plate, comprising the steps of forming a shell having raised characters on its face and corresponding recesses on its back, placing the plate adjacent a draw member, covering the back of the plate with thermoplastic material, fusing and subjecting the material to pressure to fill the recesses and forming a layer of material which extends beyond the one edge of the shell and adheres to the draw member, affixing the draw member to a carrier and drawing the plate through a shaving machine to reduce the layer to a uniform thickness, and simultaneously trimming said draw member and the excess material from the marginal edges ofsaid plate.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically illustrates a shell in cross-section having a quantity ofthermoplastic material on its back surface;

FIG. 2 schematically illustrates a cross-section through a press while the thermoplastic material is being fused and com pressed;

FIG. 3 is the top plan view of the plate after it has been removed from the press;

FIG. 4 schematically illustrates a modification of the press shown in FIG. 2;

FIG. 5 is the side elevational view schematically illustrating the shaving operation;

FIG. 6 illustrates an alternate form of the draw member; and

FIG. 7 schematically illustrates a section through a portion ofthe finished plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring, now, to the drawings in greater detail, FIG. I shows a metallic shell 10 that has been formed by electrolytically depositing a metal, such as copper, on a mold or matrix. The shell 10 thus formed has a front face 11 provided with raised characters 12 and a rear face 13 having corresponding depressions 14. Prior to insertion of the plate 10 into the press 15-16 shown in FIG. 2, particles of thermoplastic material 17, such as nylon, are applied to its rear face 13.

As seen in FIG. 2, the plate 12 and the nylon 17 are disposed between upper and lower platens 15 and 16, respectively, of the press, and a draw member 18, which may take any suitable form, such as a screen, for example, as shown in FIG. 3, is disposed adjacent one edge of the plate 10. The press 1516 may be provided with passages 20 to permit the circulation of a high temperature fluid, such as steam, and of cooling fluid. When the press 15-16 is activated to fuse the nylon 17 and compress the same, the particles 17", shown in FIG. 1, are caused to fuse into a homogeneous layer, which fills the recesses 14 in the back of the plate 10 to form a composite member 19 consisting of the plate 10 and the nylon layer 17. In addition, the nylon 17 is caused to flow onto the screen member 18 and into the perforations 21 formed therein, whereby a relatively strong bond is formed therebetween. A thin sheet of material such as metal or paper 23 may be disposed between the faces of the platens 15 and 16 and the nylon 17 to prevent adherence therebetween. If the sheets 23 are of metal, they may also be used to facilitate handling of the composite member 19.

In order to insure that the composite member 19 will have a predetermined, substantially uniform thickness, a bearer member 24 may be provided at the sides of the plate 10 as seen in FIG. 4, and between the platens l5 and 16. The bearer members 24 limit travel of the platens 15 and 16 and may be sized according to the desired thickness of member 19 and/or the number of passes to be made through the shaving machine.

After the fused nylon has cooled, the member 19 and the draw member 18, as shown in FIG. 3, is then attached to the shaving machine by means of pins 25 which pass through openings 21 in the member 18 and are slidably or threadably received in suitable apertures in the shaving machine bed 26. The bed 26 is then caused to be moved toward the right, as viewed in FIG. 5, wherein the layer of nylon 17 is caused to be engaged by a knife 27, wherein it is reduced to a uniform thickness in the manner well-known in the art.

An alternate form of the draw member 18' is shown in FIG. 6 to comprise a flat plate 18' having a first plurality of smaller apertures 21' adjacent one side for engagement by the nylon 17 and a second plurality of larger apertures 30 for attachment with the shaving machine bed 26.

After the shaving process has been completed, the excess nylon 17 is trimmed away from the marginal edges of the plate 10, which also serves to remove the draw member 18. The composite plate 19 formed is shown in FIG. 7.

It can be seen from the foregoing that the use of a draw member such as the screen 18 eliminates the necessity for a carrier plate and further eliminates the steps of cutting the plate away from the carrier member and cleaning the carrier member in preparation for an additional operation.

Iclaim:

1. In the manufacture of an electrotype printing plate, the method of forming a shell having raised characters on its face,

placing a draw member adjacent said plate and spaced therefrom, covering the back of the plate with thermoplastic material, fusing the material, subjecting the fused material to pressure to form a layer thereof on said plate, causing a portion of the material to flow beyond the edge of the shell and to adhere to said draw member, affixing said draw member to a shaving machine and drawing said shell through said machine to reduce said layer to a uniform thickness, and trimming off said portion and said draw member.

material to flow into said perforations and to adhere to the surface of said draw member to form a strong bond therewith.

4. The method set forth in claim 3 wherein means are engaged with certain of the unfilled perforations and said draw member to couple the latter to said machine for drawing said plate therethrough. 

